It is generally desirable to minimize engine noise generated from internal combustion engines. Typically, this type of noise is reduced or minimized through the use of mufflers (for reducing combustion noise emitted from engine exhaust air) and the use of resonators (for attenuating the noise generated from the engine air intake system).
One common approach to attenuating noise emitted from the intake portion of an engine, is to use resonators constructed from one or more interior chambers which are “tuned” in a way which cancels certain frequency ranges of intake noise. However, tuned resonators involve many design compromises which, invariably, make them inefficient in reducing engine noise at “non-optimum” engine speeds.
A typical resonator includes an air reservoir comprising a fixed volume connected through a neck portion which leads to the intake manifold of an engine. Baffles, tubes and other “tuning” devices are also typically included in a resonator's design. The volume of the resonator and other component dimensions are determined based on numerous factors including sound characteristics desired by the customer, component packaging within the vehicle, the number of engine cylinders, engine size, and other engine and vehicle factors that influence noise volumes and noise frequencies emitted from the air handling system of an engine.